Polarity/charge as a determinant of translocase requirements for membrane protein insertion.

The YidC insertase of Escherichia coli inserts membrane proteins with small periplasmic loops (~20 residues). However, it has difficulty transporting loops that contain positively charged residues compared to negatively charged residues and, as a result, increasing the positive charge has an increased requirement for the Sec machinery as compared to negatively charged loops (Zhu et al., 2013; Soman et al.

Safety evaluation of Bacillus coagulans SNZ 1969 in Wistar rats.

Bacillus coagulans SNZ 1969 is a rod-shaped, slightly acidophilic, gram-positive, spore forming and highly resilient bacteria. B. coagulans SNZ 1969 has GRAS (Generally Recognized As Safe) status for use as a probiotic in foods (US FDA number GRN-597).

A prospective, randomized, double-blind, placebo-controlled, parallel-group study to evaluate the efficacy and safety of SNZ TriBac, a three-strain Bacillus probiotic blend for undiagnosed gastrointestinal discomfort.

Purpose: This prospective, randomized, double-blind, placebo-controlled, parallel-group study aimed to determine the efficacy and safety of a multistrain (Bacillus coagulans [SNZ 1969], Bacillus clausii [SNZ 1971], and Bacillus subtilis [SNZ 1972]) probiotic blend (SNZ TriBac) in managing symptoms of gastrointestinal (GI) discomfort in the absence of specific pathologies.

Methods: Sixty adults with symptoms of GI discomfort were enrolled (mean age, 34.89 ± 9.

YidC/Alb3/Oxa1 Family of Insertases.

The YidC/Alb3/Oxa1 family functions in the insertion and folding of proteins in the bacterial cytoplasmic membrane, the chloroplast thylakoid membrane, and the mitochondrial inner membrane. All members share a conserved region composed of five transmembrane regions. These proteins mediate membrane insertion of an assorted group of proteins, ranging from respiratory subunits in the mitochondria and light-harvesting chlorophyll-binding proteins in chloroplasts to ATP synthase subunits in bacteria.

The role of the strictly conserved positively charged residue differs among the Gram-positive, Gram-negative, and chloroplast YidC homologs.

Recently, the structure of YidC2 from Bacillus halodurans revealed that the conserved positively charged residue within transmembrane segment one (at position 72) is located in a hydrophilic groove that is embedded in the inner leaflet of the lipid bilayer. The arginine residue was essential for the Bacillus subtilis SpoIIIJ (YidC1) to insert MifM and to complement a SpoIIIJ mutant strain. Here, we investigated the importance of the conserved positively charged residue for the function of the Escherichia coli YidC, Streptococcus mutans YidC2, and the chloroplast Arabidopsis thaliana Alb3.

Polarity and charge of the periplasmic loop determine the YidC and sec translocase requirement for the M13 procoat lep protein.

During membrane biogenesis, the M13 procoat protein is inserted into the lipid bilayer in a strictly YidC-dependent manner with both the hydrophobic signal sequence and the membrane anchor sequence promoting translocation of the periplasmic loop via a hairpin mechanism. Here, we find that the translocase requirements can be altered for PClep in a predictable manner by changing the polarity and charge of the peptide region that is translocated across the membrane. When the polarity of the translocated peptide region is lowered and the charged residues in this region are removed, translocation of this loop region occurs largely by a YidC- and Sec-independent mechanism.